The invention relates to an apparatus for superimposing and Z-folding two webs of tissue to form stacks of facial tissues for being packaged in consumer boxes.
Prior methods and apparatus for cutting and Z-folding tissue sheets are shown, for example, in Sabee U.S. Pat. No. 2,626,145. In such apparatus two continuous separate webs of tissue are perforated transversely at regular intervals in such a manner as to leave periodic tear lines in each web. The bonds of the sheets at the tear lines must be quite weak so as to be easily broken upon the exertion of a small amount of force, such as by pulling one of the stacked and interfolded tissues through the restricted opening of a dispensing box. The two webs with tear lines are superimposed in staggered relation so the tear lines of each web are positioned between the tear lines of the other web.
The superimposed webs are then Z-folded opposite each tear line so each tear line of each web is tucked into a fold of the other web. Each fold is effected by a pair of jaws and a tucker mounted on the respective sides of the superimposed webs. The tucker forces the superimposed webs between the jaws, the jaws close to capture and fold the web, the jaws carry the web to the discharge area, they open, and the interfolded tissue is released. One pair of jaws is located on each side of the web, and the pairs of jaws operate alternately on the superimposed webs to effect Z-folding.
The mechanical clamping of the sheet by the known jaws causes a sharp crease in the web and often severs it. The sheets are marred where the jaws seize the product.
Further, because of the large number of mechanical operations being performed in a given length of time by the rapidly opening and closing jaws, the speed of this type of interfolding machine is limited. At high speeds the jaws cannot be opened fast enough and the sheet can tear. The interfolded web also is not transported away from the interfolding station fast enough to allow interfolding to be performed at a high rate of speed.